Niichiro Tokura

Reactions of alkanesulphonic acid derivatives with organoalkali metal compounds : Formation and reactivity of α-sulphonylcarbanions

Abstract The effects of solvents, metals and structural variation of the substrates on the reactions between alkanesulphonic acid derivatives with organoalkali metal reagents have been examined and the formation and reactivity of α-sulphonylcarbanions are discussed. The formation of 4-membered cyclic sulphones from a sulpbonyl fluoride and the Claisen ester condensation type reaction in a sulphonic ester, which have been observed for the first time, are described.

The reaction of benzylsulfonyl halides with phenyllithium: Preparation of sulfones

Abstract The reactions of benzylsulfonyl halides with phenyllithium have been studied. The reaction of benzylsulfonyl chloride with phenyllithium in diethyl ether at 20–25° gave lithiumbenzyl sulfinate as a main product, in addition to other eight products. While the reaction of benzylsulfonyl fluoride with phenyllithium under a similar condition afforded a disulfone, α-benzylsulfonyl-α-benzenesulfonyltoluene, as a major product. On the other hand, the reactions at a low temperature (−80°) yielded a polysulfone which did not form when the reactions were carried out at an ordinary temperature. The differences of reaction courses due to a difference of a halogen content or an experimental condition are discussed, and probable mechanisms of these results are presented.

The reactions of 1,4-bis[α-diazobenzyl]benzene with sulfur dioxide

Abstract The reactions of 1,4-bis[α-diazobenzyl]benzene (I) with sulfur dioxide in aprotic solvents below ordinary temperature give the oligomer II of p -xylylidene type and 1,4-dibenzoylbenzene (III). The ratio of II to III increases with the increasing polarity of solvent in the order of petroleum ether, benzene, and tetrahydrofuran. While the reaction in the presence of water or methanol yields 1,4-bis[α-sulfobenzyl]benzene (VIII) or 1,4-bis[α-methoxysylfonylbenzyl]benzene (VII) respectively. These results appear to show that the present reactions proceed via a sulfene intermediate.

The reaction of anthracene with sulfur dioxide in the presence of benzoyl peroxide : The formation of anthracene sulfones

Abstract The reaction of anthracene with SO2 in the presence of benzoyl peroxide using n-heptane as solvent, yielded anthronyl phenyl sulfone, oligomers (anthracene polysulfones), diphenyl disulfone, benzenesulfonic acid, anthraquinone, benzoic acid and benzene. If benzene was used as solvent, the formation of the sulfones mentioned above was not observed, and instead the reaction yielded 9,10-dibenzoyloxyanthracene, dianthrone, anthraquinone, benzoic acid and a trace of benzene-sulfonic acid. These results have been interpreted in terms of a C-T complex1 of anthracene-sulfur dioxide, since the sulfones are readily formed in a solvent such as n-heptane which does not interact with SO2, whereas the formation of the sulfones is diminished in a solvent such as benzene due to its interaction with SO2.2 As in the reaction of SO2 with benzoyl peroxide using n-heptane as a solvent, diphenyl disulfone, benzenesulfonic acid, benzoic acid, benzene, phenyl benzoate and diphenyl disulfide were isolated; the yields of diphenyl disulfone, benzenesulfonic acid and diphenyl disulfide being derived from the phenylsulfonyl radical were larger than those obtained from the reaction with anthracene, the phenyl radical readily reacts with SO2 in the absence of anthracene, but the formation of the phenylsulfonyl radical is diminished in the presence of anthracene. And these results might be interpreted in terms of the interaction of anthracene with SO2 rather than with the phenyl radical, because phenylanthracene derivatives did not form but some anthracene sulfone was obtained.

The thermal reaction of phenylazotriphenylmethane and naphthylazotriphenylmethane derivatives with sulphur dioxide

Abstract The thermal reaction of phenylazotriphenylmethane, (I), with SO 2 in benzene or n-heptane gives triphenylmethyl phenyl sulphone (II) in good yield. This reaction is suppressed by a radical scavenger such as n-butylmercaptan to give n-butyl triphenylmethyl sulphide. The kinetic data obtained from the decomposition of I in liquid SO 2 does not differ much from the data in toluene. However, when two crossed reactions were carried out using two chemically labelled azo compounds in each case, the respective crossover compounds were not observed, although the two azo compounds chosen decomposed at approximately the same rate. Moreover, the intermolecular coupling product, diphenyl disulphone, was not formed. These facts suggest that the formation of II is not a 4-center type configuration or an intermolecular radical mechanism, but through an intramolecular radical reaction due to a special cage of SO 2 . The evidence that II could be derived from the phenylsulphonyl radical rather than from the triphenylmethylsulphonyl radical was obtained from the fact that the triphenylmethyl radical (π-character radical) formed from 1-diphenylmethylene-4-trityl-2,5-cyclohexadiene (Gombergs trityl) does not react with SO 2 , but does react with O 2 to give bis-triphenylmethyl peroxide. On the other hand, the reaction of I with SO 2 in the presence of O 2 yields p -hydroxytetraphenylmethane and benzenesulphonic acid, but neither II nor bis-triphenylmethyl peroxide are formed, suggesting that the reaction in the presence of SO 2 and O 2 is ionic. Also, the addition of iodine to the system (I-SO 2 -benzene or n-heptane) does not suppress the formation of II. This may be interpreted that iodine does not act as a scavenger, since iodine forms a complex with SO 2 Moreover, phenylazotriphenylmethane and naphthylazotriphenylmethane derivatives when treated with SO 2 in benzene give the corresponding sulphones. In these reactions, it was shown that σ-character radicals ( p -methoxy, p -chloro, and m -nitrophenyl radicals, or α- and β-naphthyl radicals) react with SO 2 to give sulphonyl radicals. In this case, the α-naphthyl radical reacts sluggishly owing to the steric effect of the peri -position of naphthalene ring.